Eric should have at least posted a link to this year's robot's picture.
http://www.chiefdelphi.com/forums/pi...&quiet=verbose
As you can see, the drive train is thoroughly protected. Besides, at half-inch thick, lexan is bulletproof. So at 3/8" i'd hope it'd be strong enough to take a hit from another robot. Another bit of info...two years ago we made our robot completely out of polycarb. That's right people, no structural metal at all. Here's a link.
http://www.chiefdelphi.com/forums/pi...&quiet=verbose